Urethane Methacrylate Coating for Scratch and Hair Dye Stain Resistance

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Solution Overview

Problem

Existing coating agents fail to provide a coating layer with excellent scratch resistance, stain resistance, particularly against hair dyes, and workability simultaneously.

Innovation Solution

A urethane (meth)acrylate with a cyclic structure content of 10% by weight or more and an average number of functional groups between 3.5 and 4.5, used in an active-energy-ray-curable resin composition, which forms a coating layer with enhanced scratch resistance and stain resistance, including against hair dyes, and maintains workability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional coating agents are used to form hard coating layers with scratch resistance, then scratch resistance is improved, but stain resistance against hair dyes becomes insufficient

Engineering Contradiction:
Improvescratch resistanceVSAvoidstain resistance against hair dyes
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the cyclic structure content (10-40% by weight) and the average number of functional groups (3.5-4.5) of the urethane (meth)acrylate. This specific parameter range optimization resolves the contradiction by achieving both scratch resistance and hair dye stain resistance simultaneously, which conventional coating agents fail to do.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining the specifically structured urethane (meth)acrylate with particular photoinitiators and optional additives. This composite resin composition approach enables the coating layer to exhibit both hard coating properties for scratch resistance and chemical resistance for stain resistance against hair dyes.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If conventional coating agents are used to achieve stain resistance, then stain resistance is improved, but workability and flexibility become insufficient

Engineering Contradiction:
Improvestain resistanceVSAvoidworkability and flexibility
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent resolves this contradiction through parameter changes by controlling the cyclic structure content at 10-40% by weight and the average number of functional groups at 3.5-4.5. These specific parameters enable the coating to maintain both stain resistance and excellent workability, including flexibility for curved surfaces and embossing processing.

Inventive Principle:
Principle #35Parameter changes

3Strength

If high functional group density is used to improve crosslinking and hardness, then scratch resistance is improved, but stain resistance against hair dyes becomes insufficient

Engineering Contradiction:
Improvescratch resistanceVSAvoidstain resistance against hair dyes
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the average number of functional groups to a specific range of 3.5-4.5, rather than simply increasing it. Combined with the cyclic structure content control (10-40% by weight), this parameter optimization achieves the balance between crosslinking density for scratch resistance and chemical resistance for hair dye stain resistance.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The urethane (meth)acrylate-based coating layer achieves superior scratch resistance, stain resistance, and workability, effectively protecting surfaces from scratches and stains while allowing for processing like embossing.

Implementation Method 1

active-energy-ray-curable resin composition

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11028285B2Urethane (meth)acrylate and active energy ray-curable resin composition
Publication Date: 2021.06.08 DAICEL ALLNEX

AI summary

Provided is a compound capable of forming a coating layer that has excellent scratch resistance and still has stain resistance (in particular, stain resistance against hair dyes) and workability (impact resistance) both at satisfactory levels.The urethane (meth)acrylate has a cyclic structure in a molecule. The urethane (meth)acrylate has a total weight of carbon, oxygen, nitrogen, and sulfur atoms constituting the ring or rings of the cyclic structure of 10 percent by weight or more based on the total amount (100 percent by weight) of the urethane (meth)acrylate. The urethane (meth)acrylate also has an average number of functional groups of 3.5 to 4.5.